Can confirm. Playing Elden Ring on OpenSUSE Tumbleweed. Just installed the Steam flatpak, enabled proton, installed the game, works just as well if not better than my Windows install. Nothing extra to install gpu driver wise this is practically vanilla OpenSUSE install with Steam really the only extra thing, playing online with multiplayer summons, etc.
There's also the fun approach which Valve had for 10 years in CSGO until CS2 release. They just didn't run anticheat on Linux clients meaning an opensource cheat was absolutely undetected for years.